Greater Lake Ballinger/McAleer Creek Watershed Study STRATEGIC ACTION PLAN. Project #31325

Transcription

1 Greater Lake Ballinger/McAleer Creek Watershed Study STRATEGIC ACTION PLAN Project #31325 By Otak, Inc. Golder Associates, Inc. Clear Creek Solutions, Inc. EnviroIssues July 10, 2009

2 Preface The Lake Ballinger/McAleer Creek Watershed Forum Staff Committee is pleased to present this Strategic Action Plan addressing water flow, water quality and habitat preservation options for the Lake Ballinger/McAleer Creek Watershed. This document was commissioned by the Lake Ballinger/McAleer Creek Watershed Forum under the authority of an Interlocal Agreement for jurisdictions within the greater Hall Lake, Hall Creek, Chase Lake, Echo Lake, Lake Ballinger, McAleer Creek Watershed. The Watershed Forum represents six local jurisdictions within the Watershed including Edmonds, Lake Forest Park, Lynnwood, Mountlake Terrace, Shoreline and Snohomish County. The Strategic Action Plan is the product of collaborative discussions among elected officials, jurisdictional staff, regulatory agencies local interest groups, local homeowner associations and concerned citizens. The Action Plan offers a suite of options to local governments in the Watershed Forum to address local surface and surface water issues. It is both a conceptual strategy and an associated action plan for addressing identified water resource issues and enhancing the natural functions in a highly developed urban watershed. Please note that the Action Plan provides guidance and is not a binding legal document. Each jurisdiction can choose to adopt or implement any or all of the recommendations according to their current capital and operational programs. Opportunity for additional public input will be available as the member jurisdictions consider the Plan. Citizens, businesses and non-profit organizations have and will continue to play a vital role in implementing many of the actions and may be asked or encouraged to participate in actions on their own. The Forum Staff Committee would like to thank the State Legislature and the Washington State Department of Ecology (Ecology) for assistance in developing the Action Plan. The Action Plan process was funded by a $200,000 legislative appropriation that was administered by Ecology.

3 Acknowledgements Participating Agencies City of Edmonds City of Lake Forest Park City of Lynnwood City of Mountlake Terrace City of Shoreline Snohomish County Department of Ecology Forum Members City of Mountlake Terrace: Jerry Smith, Mayor Forum Chair City of Lake Forest Park: Don Fiene, Councilmember Forum Co-Chair City of Edmonds: D.J. Wilson, Council President City of Lynnwood: Lisa Utter, Councilmember City of Shoreline: Janet Way, Councilmember Chris Eggen, Councilmember Snohomish County: Marcia Isenberg, Chief of Staff, County Council Staff Committee Members City of Edmonds: Jerry Shuster, P.E., Stormwater Engineering Program Manager City of Lake Forest Park: Aaron Halverson, Engineering and Stormwater Technician City of Lynnwood: Jared Bond, Environmental Program Manager City of Mountlake Terrace: Mike Shaw, Stormwater Program Manager City of Shoreline: Rika Cecil, Environmental Program Coordinator and Brian Landau, Surface Water and Environmental Program Manger Snohomish County: Gene Williams, Surface Water Management Department of Ecology: Doug Wood, Water Resources Program L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m

4 Acknowledgements City of Edmonds: City of Lake Forest Park: City of Lynnwood: City of Mountlake Terrace: City of Shoreline: Additional City Representatives Noel Miller, P.E., Public Works Director Dave Hutchinson, Mayor David Cline, City Administrator Neil Jensen, City Engineer Bill Franz, Public Works Director John Caulfield, City Manager Curt Brees, Public Works Director Jesus Sanchez, Public Works Operations Manager Funding for this project was provided by the Washington State Legislature through Department of Ecology Grant No. G L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m

5 Table of Contents Section 1 Introduction... 1 Section 2 Approach: A Watershed Based Strategy... 9 Section 3 Watershed Characterization Section 4 Development/Selection of Potential Actions Section 5 Elements of the Strategic Action Plan Section 6 Implementation of the Strategic Action Plan Section 7 Action Initiatives Section 8 Summary and Conclusions Section 9 References Appendices Appendix A: Governing Documents Interlocal Agreement Budget Note Ecology Grant Appendix B: Lake Ballinger Fact Sheet Appendix C: Public Process Stakeholder Interviews Forum and Public Meeting Presentations Anecdotal Information Received from Public List of People Providing Comments at March 24 and May 26 Forum Meetings Appendix D: Technical Memorandum #1 Watershed Characterization and Analysis Appendix E: Technical Memorandum #2 Planning and Pre-Engineering Strategies and Costs Appendix F: Project Selection and Evaluation Process Appendix G: Draft Strategic Action Plan Comments L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m

6 Section 1 Introduction This document presents the Strategic Action Plan for the Greater Hall Lake, Hall Creek, Chase Lake, Echo Lake, Lake Ballinger, and McAleer Creek Watershed. It is both a conceptual strategy and an associated action plan for addressing identified water resource issues and enhancing the natural functions in a highly developed urban watershed. Project Location The Watershed Area for this project covers the drainage areas for Hall Lake, Hall Creek, Chase Lake, Echo Lake, Lake Ballinger, and McAleer Creek. Lake Ballinger is located in south Snohomish County within the Cities of Edmonds and Mountlake Terrace. The full Watershed Area encompasses 5,249 acres. Approximately 3,566 acres of urbanized area drains into Lake Ballinger. This includes portions of the Cities of Lynnwood, Edmonds, Mountlake Terrace and Shoreline as well as a portion of unincorporated Snohomish County. McAleer Creek, Lake Ballinger s only outlet, travels through the cities of Mountlake Terrace, Shoreline, and Lake Forest Park, where it flows into Lake Washington (Figure 1-1 and 1-2). L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 1

7 Puget Sound 5Th Ave S E D M O N D S Main St Chase Lake U N I N C O R P O R A T E D S N O H O M I S H C O U N T Y S N O H O M I S H C O U N T Y K I N G C O U N T Y Legend!(104 84Th Ave W McAleer Creek Watershed City Boundary County Boundary Major Arterial Streams 196Th St SW 76Th Ave W S H O R E L I N E Echo Lake!( 99 N t h S t N t h S t S E A T T L E!( Th St SW M O U N T L A K E T E R R A C E Lake Ballinger N E t h S t t h A v e N E Hall Lake L Y N N W O O D 236Th St SW 48Th Ave W B a l l i n g e r W a y N E N E t h S t Larch Way B R I E R L A K E F O R E S T P A R K McAleer Creek Lyon Creek B o t h e l l W a y N E 6 1 s t A v e N E Lake Washington Logan Road 6 8 t h A v e N E B O T H E L L K E N M O R E ³ FIGURE Miles LAKE BALLINGER WATERSHED STUDY STRATEGIC ACTION PLAN 1-1 VICINITY MAP APRIL 2009 K:/project/31325/GIS/mxds/Strategic Action Plan

8 1 5 t h A v e N E L Y N N W O O D E D M O N D S!( 99 Main St Chase Lake 76Th Ave W 212Th St SW Hall Lake M O U N T L A K E T E R R A C E 212Th St SW 48Th Ave W 5 Larch Way U N I C O R P O R A T E D S N O H O M I S H C O. 228Th St SW 84Th Ave W 236Th 236Th St SW B R I E R!( 104 Lake Ballinger S R N E t h S t S N O H O M I S H C O U N T Y M C A L E E R C R E E K W A T E R S H E D K I N G C O U N T Y Echo Lake B a l l i n g e r W a y N E L A K E F O R E S T P A R K Lyon Creek 6 1 s t A v e N E!( 99 S H O R E L I N E Legend N t h S t McAleer Creek Watershed 5 N E t h S t McAleer Creek B o t h e l l W a y N E City Boundary County Boundary Major Arterial Lake Washington Streams Parcel Boundary NAIP Photography 2006 LAKE BALLINGER WATERSHED STUDY ³ Miles Disclaimer: The information shown in this map is assembled GIS data created and acquired by Otak Inc., and from City of Lake Forest Park GIS. This data is not to survey accuracy and is meant for planning purposes only. K:/project/31325/GIS/mxds/Strategic Action Plan APRIL 2009 STRATEGIC ACTION PLAN FIGURE 1-2 STUDY AREA

9 Section 1 Introduction Continued Project Background Lake Ballinger has a history of flow control that goes back to a 1942 Superior Court Order calling for installation of a weir to set lake levels and control shoreline flooding. In 1982, the Superior Court Order was readjudicated and a lake restoration plan was developed to address ongoing lakeshore flooding issues, as well as water quality issues related to 40 years of development in the lake basin. However, flooding has continued to be a problem for a number of lakeside property owners during large storm events. Downstream in the City of Lake Forest Park, extensive commercial and residential properties have been periodically damaged in the Towne Centre and Sheridan Beach neighborhoods. Four of the six participating jurisdictions have reported major flooding within the watershed during large storm events. Financial loss due to flooding has been substantial during storm events for many residents and businesses in the watershed. In the December 2-3, 2007 event alone between $150,000 and $250,000 in damage to homes was experienced on Hall Creek and Lake Ballinger (City of Mountlake Terrace and City of Edmonds. 2009) More than $4 million in damage was reported in the lower reaches of McAleer Creek at Lake Forest Park Towne Centre and Sheridan Beach (City of Lake Forest Park. 2009) The financial loss estimates are based on information collected from residents and businesses and include only loss due to physical damage. No estimate of loss other than physical damage due to flooding was evaluated as part of this study. In addition, water quality has been an issue within the Lake Ballinger/McAleer Creek watershed for more than thirty years. In the lake, algae blooms, associated with depressed dissolved oxygen levels and decreased clarity in the water column are a periodic occurrence. Monitoring of McAleer has indicated degraded water quality from detectable levels of metals, pesticides, petroleum products, and coliform bacteria. Habitat has been impacted in both Lake Ballinger and McAleer Creek from pollutants in urban runoff. The creek has been impacted by scouring flows from large volumes of urban runoff during large rain events. During the 2008 legislative session, the State of Washington allocated funding to Ecology to study surface water and groundwater effects on the level of Lake Ballinger (Appendix A). This appropriation was in response to the concerns of citizens regarding historical flooding and water quality issues in and around the Lake. With support from the Ecology grant, six jurisdictions came together in the summer of 2008 to address long-term watershed planning for the entire watershed area. An Interlocal Agreement (ILA) was signed and approved by the legislative bodies representing the cities of L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 4

10 Section 1 Introduction Continued Edmonds, Lake Forest Park, Lynnwood, Mountlake Terrace and Shoreline, and Snohomish County. This ILA created the Greater Hall Lake, Hall Creek, Chase Lake, Echo Lake, Lake Ballinger, McAleer Creek Watershed (Forum). The complete ILA is presented in Appendix A. The ILA calls for the following: Creation of a group of elected officials, representing each of the six participating agencies (the Forum), to lead the study and approve and implement the Strategic Action Plan. Establishment of the Staff Committee, representing each member jurisdiction, to carry out actions as directed by the Forum. Development of a Strategic Action Plan by the Staff Committee to identify specific actions and projects to address the identified water resources issues within the watershed area. Approval of the final Strategic Action Plan by the Forum within 60 days of receiving the plan from the Staff Committee. After approval by the Forum, the Strategic Action Plan shall be referred to the legislative body of each Member Jurisdiction for consideration and adoption. (Note: In the event the Strategic Action Plan is not approved, it shall be returned to the Staff Committee for further consideration and amendment and thereafter returned to the Forum for decision.) Based on a grant agreement between Ecology and the City of Edmonds (the Forum s designated fiscal agent) the Strategic Action Plan is to be completed by June 30, To this end, the Forum Technical Staff Committee implemented a consultant solicitation process and recommended to the Forum that Otak, Inc. be selected to provide technical support for development of the Strategic Action Plan. The Forum approved the selection of Otak, Inc. (with subconsultants Clear Creek Solutions providing hydrologic/hydraulic modeling, Golder Associates providing groundwater/infiltration analyses, and EnviroIssues providing public involvement support) and the project s scope of work at the August 26, 2008 Forum meeting. The scope of work is included in the approved Ecology grant provided in Appendix A. The project scope of work included a three part process: watershed characterization, planning and pre-engineering, and development of the strategic plan (discussed in Section 2). During the eight months of this project, the Forum included numerous opportunities for the public to provide input into the plan development. Details on public involvement activities for this project are presented in Section 2 and Appendix C. The results of this process included two technical memoranda (presented Sections 3 and 4) published to give the public and Forum members opportunities to provide input on the project prior to the development L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 5

11 Section 1 Introduction Continued of the Strategic Action Plan. This Strategic Action Plan document is the final step in the scope of work. Past Studies and Projects Two studies conducted by Municipality of Metropolitan Seattle (Metro) (now part of King County) identified Lake Ballinger as having the poorest water quality of any of the Seattle area lakes (Metro 1973 and 1976). A 1974 study reported that the very large volumes of runoff from the Lake Ballinger watershed are a function of the highly urbanized land use (39 percent developed at that time) and the dominance of impermeable soil in the basin (Stevens, Thomson & Runyan, 1974). A 1977 study states that Lake Ballinger suffers from a history of pollution related to urbanization and poor land development practices in the basin (KCM 1977). These studies show the negative consequences of urban land use practices on receiving waters. These studies from over 30 years ago also document that the Lake Ballinger watershed was largely built-out prior to local jurisdictions requiring developers to control the quantity and quality of stormwater runoff, which began in the late 1970s and early 1980s. This uncontrolled runoff from urbanized residential and commercial land use and the associated roads are a primary cause of the issues and concerns identified by stakeholders and residents for this project. A record of notable events regarding the Lake Ballinger watershed was compiled in August 2004 and updated in January As a result of studies published in the 1970s, the City of Mountlake Terrace developed a Lake Ballinger Restoration Project funded by the Washington State Department of Ecology along with the Federal Environmental Protection Agency to address flooding and water quality issues. Water quality information gathered as a part of the Restoration Plan Final Report in 1986 led in part to the Department of Ecology issuance of a Total Maximum Daily Load (TMDL) limit for total phosphorous in In 2007, the cities of Mountlake Terrace, Edmonds and Shoreline commissioned a Lake Ballinger Lake Level Study. This information is presented in Appendix B. The project website 1 contains many of these past studies that document historic conditions and challenges within the Watershed Area. In addition, Technical Memorandum #1 (Appendix D) includes a table of previous reports and studies related to the Lake Ballinger/McAleer Creek watershed. A detailed history of flooding conditions in the Watershed Area is included in Technical Memorandum #2 (Appendix E). A table recording lake level elevations and their significance was provided to the Forum at the January 29, 2009 briefing. 1 L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 6

12 Section 1 Introduction Continued In addition, considerable project and volunteer effort has been put forward by a number of stakeholder groups in the watershed. These groups include homeowners associations, notfor-profit foundations and citizen groups from several cities in the watershed. The contribution from these groups is seen in a number of areas including invasive vegetation control, habitat enhancement along stream banks, public education and public outreach. Cooperation and support from these stakeholders is crucial to the success of the Strategic Action Plan process. Project Objectives The initial objective of this study was to develop a Strategic Plan to address the flooding of homes around Lake Ballinger and the homes and commercial area along the lower reaches of McAleer Creek. The secondary objectives of water quality, fish/habitat, and stream/lake assessment and enhancement were included at the request of the public as the study progressed. Based on stakeholder input and the support of the Forum, the Strategic Action Plan includes water quality and fish/habitat issues within the Watershed Area. This approach has resulted in a more holistic approach to watershed enhancement and has provided policy makers with additional project options to meet the desired objectives of flood reduction, water quality, and habitat improvement. Due to funding and schedule issues, analysis of flood reduction, water quality and habitat improvement issues have been included at a conceptual planning level. The outcomes of Strategic Action Plan will be: A prioritized list of activities to be implemented for each of the four identified water resource related issues: o Issue A Lake Ballinger/Hall Creek: Flooding o Issue B Lake Ballinger: Water Quality/Habitat o Issue C McAleer Creek: Downstream Flooding o Issue D McAleer Creek: Downstream Water Quality/Habitat Suggested recommendations for implementation and funding. An initial set of highly ranked short term actions that can be implemented within the next 1-3 years to begin addressing the identified water resources issues. A composite listing of additional short, medium and long-term actions for the Forum to prioritize and implement as future funding is realized. Structure and Content L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 7

13 Section 1 Introduction Continued This report is built upon the results and findings presented in Technical Memorandum #1 Watershed Characterization and Analysis and Technical Memorandum #2 Planning and Pre-Engineering Strategies and Costs. Results, findings, activity options and recommendations have been organized according to each of the four issues identified for enhancement within the Watershed. Based on the public/stakeholders feedback regarding Technical Memorandum #2, this Strategic Action Plan has been prepared for short (1-3 years), medium (4-6 years), and long-term (greater than 6 years) funding and implementation. Rating and ranking criteria presented in the following methodology were used to prioritize each watershed enhancement activity. The Strategic Action Plan presents a compilation of all candidate activities received throughout the planning process; no proposed activity was eliminated. Thus, the Strategic Action Plan contains all suggested candidate activities for watershed enhancement received to date. All documents and technical presentations developed during this project have been included in the appendices. These include Technical Memoranda, public meeting comments and presentations made to the Forum. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 8

14 Section 2 Approach: A Watershed Based Strategy Methodology This project uses a watershed based approach to identify the problems and develop solutions that will address existing flooding problems and work toward the long term enhancement of the Watershed Area. The process provides an initial technical basis to document how the watershed has changed, how the land use conditions have transformed and increased the flows within the watershed, and what potential solutions are needed to reduce major flooding during larger runoff events. Figure 2-1 shows the project flow chart consistent with the approved scope of work. A summary of the steps in the Strategic Action Plan development are outlined below. Additional detail and information is included in the following sections of this report. Figure 2-1: Project Flow Chart Brainstorming Issues and Concerns The first task in development of the Strategic Action Plan solicited public input to identify the major water resource issues and concerns. The result of this task was an issue matrix presented in Figure 2-2 outlining the issues, goals and possible causes identified during this planning process. Four issues were identified for this study: o Issue A Lake Ballinger/Hall Creek: Flooding o Issue B Lake Ballinger: Water Quality/Habitat o Issue C McAleer Creek: Downstream Flooding L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 9

15 Section 2 Approach: A Watershed Based Strategy Continued o Issue D McAleer Creek: Downstream Water Quality/Habitat Figure 2-2: Watershed Issues Matrix Watershed Characterization Following the development of the issues matrix, the project team characterized the watershed using a water balance approach to assess the surface and groundwater flows in the basin. This information was used to describe the interaction between surface runoff, groundwater flows, and creek flows and their relationship to historic flooding on Hall Creek, along the southeastern shore of Lake Ballinger, and downstream near the mouth of McAleer Creek (Technical Memorandum #1 See Appendix D). This step also included the development of watershed base maps, updating of the existing hydrologic model of the watershed for current land use conditions, and an evaluation of hydrogeologic conditions within the Watershed Area. Development of Potential Actions Technical Memorandum #2 Planning and Pre-Engineering Strategies and Costs, built upon the information presented in Technical Memorandum #1, and was used to identify, evaluate, and rank potential watershed enhancement actions. It includes a listing of the potential actions, organized by each of the four watershed issues. Technical Memorandum #2 focused on evaluating potential actions to address flooding and property impacts that occur during peak flow events. Comments and additional project suggestions were provided by a number of stakeholders and citizens to expand the focus of the analysis to include projects to also address habitat and water quality concerns. Their comments were included L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 10

16 Section 2 Approach: A Watershed Based Strategy Continued as part of a more comprehensive approach for the enhancement of the watershed and its natural functions. Integrated Solutions and Implementation Priorities Based on Technical Memoranda #1 and #2, and on input provided by project stakeholders, the project team developed a comprehensive list of potential actions that could provide benefit or improvement to one or more of the four identified watershed issues. The Forum, Staff Committee, and other interested stakeholders and citizens worked to define implementation priorities based on long term watershed goals and select the potential actions that would best address those priorities. Short, medium, and long term implementation steps to complete the selected actions were identified (See Section 5). Overall, the project approach aims to review a wide range of possible solutions. Highly ranked solutions were selected to address each of the four key issues in the watershed. The recommended actions will be implemented based on the priorities set by the Forum members. Ongoing coordination between Forum members and continual review and update of the implementation priorities will be needed to ensure long term project success. Multi-Jurisdictional Involvement This comprehensive strategy required a multi-jurisdictional approach, with each participating City and County providing representatives to the Forum and to the Staff Committee. Forum members were involved throughout the process, identifying watershed issues, providing background information and technical studies, reviewing potential actions, and selecting high priority projects. At the completion of this study, Forum members will continue to lead the review, selection, funding and implementation of the Strategic Action Plan priorities. Past Activities A comprehensive list of stormwater related activities undertaken by member jurisdictions is listed in Section 7 of the plan. Many of these activities incorporated the latest in state of the art stormwater practices at the time they were enacted. Stormwater management practices have developed and matured significantly in the last 10 years. All member jurisdictions are now required to meet the water quality provisions of the National Pollution Discharge Elimination System (NPDES) Phase II permit requirements. All member jurisdictions are also required to adopt a stormwater management manual that meets State guidelines. New regulatory requirements will result in greater uniformity and success in the preservation of water quality and the control of storm flow from new development and redevelopment projects. This plan will ensure that new regulation utilizing a best available science approach is incorporated by member jurisdictions at the watershed level. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 11

17 Section 2 Approach: A Watershed Based Strategy Continued Public Involvement A summary of the public involvement activities is included below. Additional supporting information (stakeholder interviews, copies of presentations, etc) is included in Appendix C. An initial public meeting was held on November 12, 2008 at the Ballinger Lake Golf Course in Mountlake Terrace to present an overview of the approach for development of the Strategic Action Plan. The meeting included a facilitated discussion on the public s hopes for the Plan and its potential outcomes. A project stakeholder list was developed and an distribution list created. s were sent to the list to announce documents available for review, Forum meetings and public opportunities to comment. A publicly-accessible project web page 2 was created in mid-november 2008 to provide document references, meeting notices, and opportunities for public comment. Draft Technical Memorandum #1 (Watershed Characterization and Analysis) was posted in January Draft Technical Memorandum #2 (Planning and Pre-Engineering Strategies and Costs) was posted in February Comments on these documents were solicited from Stakeholders, the general public, and Member jurisdiction though April 13, All public comments were included in the appendix to Technical Memorandum #2. The Forum Staff Committee received additional input from several environmental groups within the watershed. Their comments regarding additional approaches to the flooding issues and expanded suggestions on incorporating water quality and habitat issues are included as an Appendix to Technical Memorandum #2 (Appendix E). The March 24, 2009 Forum meeting was expanded to solicit public comment on the body of work to date. A list of those providing comment is included in Appendix C, and the letters of comment have been included in Technical Memorandum #2. The draft Strategic Action Plan was placed on the project website on May 12, A public meeting was held on the draft plan on May 20, The Staff Committee finalized the plan in June L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 12

18 Section 3 Watershed Characterization Approach Step 1: Watershed Characterization Task 1 in the development of the Strategic Action Plan was the completion of a watershed characterization and analysis to provide background technical data to support the development of the action plan. The major activities included with the watershed characterization were: Data collection and analysis. Development of base maps and GIS overlays of the Watershed Area. Assessment of existing data and definition of outstanding data needs. Completion of an existing conditions watershed assessment, including updating the existing HSPF hydrologic model for the watershed area. Evaluation of hydrogeologic conditions (based on information obtained from drilling a monitoring well) to determine fluctuations of lake and groundwater water levels in the winter months. Analysis of flows to characterize how surface and groundwater move through the watershed area under current (developed) conditions and pre-urbanization forested conditions. Identification of important flow control areas within the Watershed Area. Identification of locations of flooding within the Watershed Area and determination of frequency of flooding. Watershed Characterization: Results and Key Findings The results of the watershed characterization are presented in Technical Memorandum #1. Some of the key findings from the watershed characterization are listed below. The full report and detailed analysis can be referenced in Appendix D. Lake Ballinger Water Balance The Lake Ballinger drainage basin contains 3,567 acres and constitutes 68 percent of the total 5,250 acres that make up the McAleer Creek watershed. The movement of surface water within the Lake Ballinger/McAleer Creek watershed area has been substantially altered from forested, undeveloped conditions. In a forested state, the volume of water entering the lake was estimated to be 4,946 acrefeet/year, and was due primarily to groundwater (72 percent). Additional water from interflow (25 percent) and direct rainfall (3 percent) entered the lake, with almost no surface runoff. In the current (developed) condition, the volume of water entering the lake is projected to increase to 7,043 acre-feet/year, and is divided between groundwater (25 percent), interflow (17 percent), direct rainfall on (2 percent), and surface and impervious water runoff (56 percent). L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 13

19 Section 3 Watershed Characterization Continued The water balance analysis shows that evapo-transpiration accounts for 6,353 acre-feet in the forested condition and only 4,220 acre feet in the current (developed) condition, a decrease of about 34 percent. Due to the removal of native vegetation and soils, and the concurrent construction of impervious surfaces throughout the watershed, there is a net increase of about 42 percent more water entering the lake on an annual basis under current (developed) conditions than under forested conditions. Most of this new additional water is from surface and impervious runoff which did not exist under forested conditions. Based on the severity and magnitude of the alterations throughout the Watershed Area, it is not likely that the natural water balance can be re-established without eliminating impervious surfaces and reestablishing native vegetation and soils. McAleer Creek Capacity The flow conveyance capacity of the lower reaches of Lyon Creek in the vicinity of the Towne Centre is significantly undersized. The most undersized culvert can pass only those flows associated with storms less than the 2 year, 24 hour event. Lyon Creek appears to be one of the primary sources of flooding for the lower reach of McAleer Creek in and near the Lake Forest Park Towne Centre, where excess surface water leaves Lyon Creek and spills into McAleer Creek just upstream of Bothell Way near the Fire Station. If excess surface water flows from Lyon Creek are contained within the Lyon Creek watershed, the existing drainage system of lower McAleer Creek has the capacity to pass flows associated of up to the 50 year, 24 hour storm event. There is only one culvert (M585) in the Sheridan Beach neighborhood that limits the capacity of the system to a 50-year event, 24 hour storm event. Groundwater Assessment Groundwater within the watershed is hosted in relatively porous glacial outwash soils composed primarily of sand and gravel. Groundwater contributes to stream baseflows and to base lake levels, particularly where surface water bodies are in close proximity to outwash deposits. Slower flow rates of groundwater allow for a time lag after rain events that mitigates the effects of groundwater on flooding within the basin. In the northwest portion of the watershed above Lake Ballinger, along Highway 99, outwash soils are either exposed at the surface or occur beneath feet of till (stony, clay-rich soils). Outwash aquifer water levels suggest that these shallow outwash deposits may be available for infiltration of excess surface water runoff. The water infiltrated in this area will likely discharge via groundwater into Hall Creek and Lake Ballinger, and the lower reaches of McAleer Creek, but would not likely affect flooding due to the time lag resulting from slower groundwater flow rates. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 14

20 Section 3 Watershed Characterization Continued Water Quality Assessment Water quality and habitat functions of Lake Ballinger and the downstream reaches of McAleer Creek have been degraded by urbanization within the watershed. While Lake Ballinger currently meets the phosphorus levels required in the TMDL that has been established for the lake by Ecology, the lake experiences summer algae blooms, which impact water quality and interfere with the recreational uses of the lake. Key Watershed Issues Following the watershed characterization, the Staff Committee reviewed the data and analysis and identified the four key watershed issues to be addressed in the Strategic Action Plan. Next, the staff committee developed specific objectives and a list of possible causes related to each of the identified watershed issues. A detailed table of the watershed issues, goals, and causes is included in the Technical Memorandum #2 presented in Appendix E of this report. The project team also outlined service criteria for each watershed issue to define how much flow reduction or water quality improvement is needed to achieve specific desired objectives. For each major watershed issue, Service Criterion 1 defines a short term goal that would provide a measurable benefit to the watershed. Service Criterion 2 represents the optimal, long term goal desired for the watershed. The four major watershed issues, associated goals, and service criteria are presented below. Issue A: Lake Ballinger/Hall Creek Flooding Description: Flooding of properties on Hall Creek and Lake Ballinger. Flooding can impact the living spaces of five residences and yards and docks of other residences (See Figure 3-1 for historic flooding areas around Lake Ballinger). Goal: Reduce/eliminate the frequency and severity of flooding in living spaces and yards. Service Criteria 1 Short Term: Prevent structures, such as homes, from flooding, which requires keeping the lake level below feet Service Criteria 2 Long Term: Prevent yards from flooding, which requires keeping the lake level below feet. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 15

21 Table 1 - Watershed Issues, Goals and Causes Issue Issues Description Goal Objectives Possible Causes 1. Lack of flow control causing high runoff from areas developed prior to any flow control stormwater regulations 2. Outdated stormwater flow control regulations A B C D Hall Creek/Lake Ballinger Flooding: Flooding of properties on Hall Creek and Lake Ballinger. Flooding now impacts the living spaces of three residences and yards and docks of other residences Lake Ballinger Water Quality/Habitat: Algae blooms in Lake Ballinger make it undesirable for recreation. Reduce/eliminate the frequency and severity of flooding in living spaces and yards. Improve water quality for aquatic organisms throughout the year (especially fish) and for recreational use. Downstream Flooding: Excessive flows from upstream jurisidictions combined with Downstream flows are causing flooding of downstream properties. Flooding now Reduce/eliminate the frequency and severity impacts public, commercial and residential of flooding in living spaces and yards. properties on the north side of SR 522 (Towne Centre area) and many residences on the south side of SR 522 (Sheridan Beach). Downstream Water Quality/Habitat: Improve flow regime and water quality Elevated flows have elevated degraded habitat thereby enhancing habitat and natural through scour and sedimentation; pollutant functions. loading having degraded water quality. 1. Reduce flood damage to homes, buildings and infrastructure. 3. Lack of tree vegetation cover for stormwater retention and evapotranspiration. 4. Lower priority given to maintaining existing infrastructure compared other services provided by jurisdictions. 5. Undersized stormwater conveyance facilities pipes and culverts. 6. Encroachment/elimination of floodplain and buffer areas within natural flood storage areas. 7. Soils with limited infiltration capabilities. 1. Reduce phosphorus concentrations in Lake Ballinger. 1. Elevated nutrient input into the Lake Ballinger from fertilizers, detergents, and soil 2. Reduce phosphorus loadings. erosion promote algae growth. 3. Implement/comply with the Lake Ballinger Phosphorus TMDL 1. Lack of flow control causing high runoff from areas developed prior to any flow control stormwater regulations 2. Outdated ted stormwater flow control regulations 1. Reduce flood damage to homes, buildings and infrastructure. 1. Reduce peak flows from large storm events. 2. Reduce concentrations of fecal coliform, dissolved oxygen, bacteria and toxins in McAleer Creek. 3. Lack of tree vegetation cover for stormwater retention and evapotranspiration. 4. Lower priority given to maintaining existing infrastructure compared other services provided by jurisidictions. 5. Undersized stormwater conveyance facilities pipes and culverts. 6. Encroachment/elimination of floodplain and buffer areas within natural flood storage areas. 7. Soils with limited infiltration capabilities. 1. Existing levels of flow control are not sufficient to decrease high flows that increase scour and sedimentation. 2. Existing levels of water quality treatment are not sufficient to support desired level of water quality and habitat within McAleer Creek and its tributaries. 3. Natural floodplain has been encroached upon and/or eliminated. K:\project\31300\31325\Reports\TechMemo2\Table 1\Table_1_MitigationAlternativesTable_Rev_ xls

22 1 5 t h A v e N E St Legend Major Flooding Locations McAleer Creek Watershed City Boundary 212Th St SW Hall Lake 212T County Boundary Major Arterial Streams Th Ave W Parcel Boundary Chase Lake 76Th Ave W M O U N T L A K E T E R R A C E U N I N C O R P O R A T E D S N O H O M I S H C O Lake Ballinger S R 9 9 Homes that Flooded in the Dec. '97 Event. 48Th Ave W t h S t S W 236Th St SW E D M O N D S Lake Ballinger 104 N t h S t N E t h S t M C A L E E R C R E E K W A T E R S H E D Echo Lake McAleer Creek B a l l i n g e r W a y N E Aerials Express Photography 2005 LAKE BALLINGER WATERSHED STUDY STRATEGIC ACTION PLAN FIGURE 3-1 UPSTREAM AND LAKE BALLINGER HISTORIC FLOODING AREAS Miles K:/project/31325/GIS/mxds/techmemo2_jan2009 APRIL 2009

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24 1 5 t h A v e N E S N O H O M I S H C O U N T Y N E t h S t K I N G C O U N T Y Legend Major Flooding Locations B a l l i n g e r W a y N E 5 McAleer Creek Watershed City Boundary County Boundary Major Arterial Streams Parcel Boundary ELINE M C A L E E R C R E E K W A T E R S H E D L a k e F o r e s t P a r k Lyon Creek McAleer Creek t h S t S W S h o r e l i n e Lake Washington Aerials Express Photography 2005 LAKE BALLINGER WATERSHED STUDY STRATEGIC ACTION PLAN FIGURE Miles K:/project/31325/GIS/mxds/techmemo2_jan2009 APRIL 2009 DOWNSTREAM HISTORIC FLOODING AREAS

25 Section 3 Watershed Characterization Continued Issue D: Downstream Water Quality/Habitat Description: Elevated flows have degraded habitat through scour and sedimentation; pollutant loadings have degraded water quality and increased fish mortality. Goal: Improve flow regime and water quality, thereby enhancing habitat and natural functions. Service Criteria 1 Short Term: Reduce flow rates so that some critical habitat function can be restored to a level which will increase a sustainable population and healthy of fish and other aquatic organisms Service Criteria 2 Long Term: Establish an in-stream habitat environment that supports salmonids and other organisms. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 20

26 Section 4 Development/Selection of Potential Actions Step 2: Identify Potential Watershed Enhancement Actions The second step in the development of the Strategic Action Plan was to identify, rate and rank and evaluate potential actions to reduce flooding and enhance water quality. The major activities in this task were: Define the problem quantify historic flooding conditions. Define evaluation criteria to score and rank potential actions. Perform Level I analysis to identify and rank potential actions. Conduct an engineering analysis to evaluate the effectiveness of potential actions related to flood reduction. Perform Level II analysis to evaluate the highly ranked potential actions. Develop a summary of costs for each of the highly ranked potential actions. Perform a Level III analysis to select the highest ranked potential actions to recommend for inclusion in the strategic action plan. Each potential action was put through a three step planning and pre-engineering analysis, as illustrated in Figure 4-1. The analysis is summarized in this section with the complete analysis documented in the Technical Memorandum #2 presented in Appendix E of this report. Figure 4-1: Pre-Engineering Analysis Approach L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 21

27 Section 4 Development/Selection of Potential Actions Continued Following the completion of the planning and pre-engineering analysis, the results of the evaluation of potential actions were presented to the Forum, staff committee, and public for review and comment. Stakeholders provided comments and suggestions on the ranking and selection of potential actions. Those comments are included as Appendix I of Technical Memorandum #2 and were integrated into the development of this Strategic Action Plan in Section 5. Planning and Pre-Engineering Analysis The Planning and Pre-Engineering analysis presented in Technical Memorandum #2 focused on identifying and evaluating potential actions to address flooding problems around Lake Ballinger and in the lower reaches of McAleer Creek. Evaluation Criteria All potential actions developed with this project were evaluated for their possible contribution toward watershed improvement. The project team developed three major scoring and ranking criteria that were used through the planning and pre-engineering analysis as well as in the development of the projects and priorities presented in the Strategic Action Plan. The three evaluation criteria used in this project are: 1. Effectiveness The potential action s ability to reduce flooding and/or enhance water quality or habitat. 2. Cost/Benefit The value of the flow reduction or water quality benefit relative to the cost of the project. 3. Ability to Implement The complexity of design, availability of materials, level of permitting, and the need for additional technical studies. Potential conflicts with established water rights, regional watershed objectives or salmon enhancement objectives were also considered. All scoring and ranking was based on a qualitative assessment of the preliminary project concepts. The scoring methodology is discussed in Technical Memorandum #2, with more detailed information on the ranking criteria being presented in Appendix F of this report. Conceptual Methods to Address Watershed Issues After the issues, goals and the evaluation criteria were established and the service criteria and ranking/rating criteria were established, the project team worked to identify an extensive list of potential actions to address each of the major watershed issues. The process first included developing conceptual methods to address Lake Ballinger upper watershed issues as depicted in Figure 4-2 and the downstream McAleer Creek watershed issues as shown in Figure 4-3. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 22

28 Section 4 Development/Selection of Potential Actions Continued Figure 4-2: Conceptual Methods to Address Lake Ballinger Flooding Figure 4-3: Conceptual Methods to Address Downstream Flooding L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 23

29 Section 4 Development/Selection of Potential Actions Continued Three-Level Engineering Analysis After developing the conceptual ideas discussed above, additional discussions were held to develop an initial list of 116 potential actions 3 that could address one or more of the four major watershed issues. Potential actions were placed into three groups depending on the anticipated timeframe to complete the action: short-term (1-3 years), mid-term (4-6 years), and longer-term (greater than 6 years). Each action was scored based on the established evaluation criteria. This concluded the Level I engineering analysis. The Level II analysis included an engineering evaluation to gauge the potential benefit of some of the higher ranked potential actions. The engineering analysis focused on regional facilities, high flow bypass lines, and the use of low impact development (LID) techniques. The results of this evaluation were used in the Level II analysis to adjust relative rankings of potential actions. Finally, the Level III analysis looked at potential actions in further detail in terms of concept description, expected performance, phasing opportunities, conceptual cost, permitting requirements and implementation schedule. All costs are in 2009 dollars and are based on best engineering estimates. The results of the Level III analysis was a list of 17 highly ranked projects for consideration for the Strategic Action Plan. Those projects and their estimated cost are shown in Table 4-1. This was used as an initial set of preliminary recommendations to solicit comments and feedback from interested stakeholders. Table 4-1: Summary of Costs for Highest Ranked Potential Actions Potential Actions Preliminary Cost Estimate 1 Issue A: Lake Ballinger/Hall Creek Flooding 2 Flood-proofing Residents and Structures (Privately initiated) ~$800,000 (8 Homes: 5 on Lake Ballinger, 3 on Hall Creek) Purchase Flood-Prone Residential Properties $4,000,000 (8 Homes: 5 on Lake Ballinger, 3 on Hall Creek) Modify Weir at Lake Ballinger, Develop Lake Mangement Procedures $500,000 Plan 3 Develop regional/local stormwater infiltration facility (Costs $12,000,000 Dependent on Engineering Approach and Land Values) Issue B: Lake Water Quality and Habitat Water Quality Monitoring for Lake Ballinger $100,000 annually 3 The number of potential actions was expanded through stakeholder comments as presented in Technical Memorandum #2. The tables in Section 5 show the full list of all potential actions developed for this project. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 24

30 Section 4 Development/Selection of Potential Actions Continued Table 4-1: Summary of Costs for Highest Ranked Potential Actions Potential Actions Preliminary Cost Estimate 1 Continue TMDL Lake Ballinger Monitoring Already Funded Supplement Water Quality/Habitat Enhancement Plan for Lake Ballinger ~$100,000 annually Design and Build LID BMP Retrofits (one rain garden on each of the 22,000 parcels = $22 million) ~$100,000 annually Phase II Municipal Stormwater Permit Implementation Varies by Jurisidcation Issue C: Downstream Flooding Flood-proofing Residential/Commerical Structures (Privately initiated) (40 Homes) ~$4,000,000 Purchase Flood-Prone Residential Properties (20 homes) $10,000,000 Lyon Creek Towne Centre Bypass Line 4 (This cost estimate does not include any channel conveyance capacity $3,400,000 upgrades or extensive permitting costs. ) Upgrade McAleer Creek Culvert M585 4 $250,000 Issue D: Downstream Water Quality and Habitat Water Quality Monitoring for McAleer Creek $100,000 annually Water Quality/Habitat Enhancement Plan for McAleer Creek $250,000-$500,000 Design and Build LID BMP Retrofits ~$100,000 annually Phase II Municipal Stormwater Permit Implementation (see text below) Varies by Jurisidcation 1 Costs shown are preliminary planning level cost estimates and will require additional analyses to develop more accurate cost estimates. Refer to Appendix H of Technical Memorandum #2 for cost estimates. 2 Hall Creek CIP projects, already funded by the City of Mountlake Terrace will help address this problem; however, they have not been included in the Level I Analysis because they are already scheduled for implementation by the City. 3 Feasibility Study only. Excludes final design, permitting and construction costs. Costs reduced from $1M in Technical Memorandum #2 (See Table 4 of this document) to $500,000. 4Does not include channel conveyance capacity upgrades or permitting costs. All five cities have been identified by as Phase II Municipal Stormwater Permit communities and will need to comply with the requirements of the Western Washington Phase II Municipal Stormwater Permit issued January 17, Snohomish County has been identified as a Phase I Municipal Stormwater Permit community (those with a population of 100,000 or more) and must comply with the Phase I Municipal Stormwater Permit issued January 17, Implementation of both the Phase I and Phase II Permits will help 4 Lyon Creek is not in the purview of the Watershed Forum. L a k e B a l l i n g e r / M c A l e e r C r e e k F o r u m 25